I might have some pictures to send that can illustrate it better but I'll send you a PM when I get home. 3/8" steel rod and a solid welder, with some stout cage wire is all you need.
That is heavy rod, I use 1/4" but would reccomend cold rolled over mild steel rod. I'm using 1x2 wire 14 gauge. That is not considered heavy but it lighter to carry and I have had no problems with it.
Look at this:
I make the squares individually. They are attached to the screen but not to each other so I make 5 per trap, then the door which is smaller, enough to fit inside the other squares.
To make them you need to build a jig. I made my jig by drawing out the piece on some flat steel and wilding 1/2" rods 1" long in the corners. Clamp the cut to length rod in one of the corners. Heat the rod with a torch where you want to bend and form it . Weld the corners where the ends come together except for the door frames and doors. You need to keep those open until you put the springs and hinges on. Here's what my door springs look like:
The springs are #2 music wire springs but you can use #1 1/2 springs. I think Bernie only uses one per door, I use two. You'll probably have to sit down and figure out how to place the springs if you use them. You can also use gravity drop doors. They work for beaver. Springs are better for otter. Work for beaver too. All my opinion.
No springs you will have to use Bernies trigger. I don't have a picture. Strong springs, I use this kind:
Not the best picture I know, 220 dog and trigger with the trigger wire replaced with 1/8" cold rolled.
Hey it's not all diagramed but those are the pics I have before me and you'll need to figure some of it out yourself so you feel like you really acomplished something.
